Patent GB-628529-A (GB)
Title: Improvements in and relating to methods of and apparatus for manufacturing flash lamps
IPC: F42B3/198
Filed: 1945-02-23
Abstract: Fulminating material is applied to the two inner leads of a photoflash lamp mount moved by a carrier 10 through a number of stations A-Y in two coats, the second of which forms a bridge which is broken by an air blast.  The mount comprises a glass stem 28, Fig. 2, an exhaust tube 24 and a pair of lead in wires 30 bridged by a filament 31 of tungsten.  The mounts are supported on heads 19, Fig. 1, mounted on the carrier 10 rotatable on a shaft 11.  An operator places mounts in the heads at loading stations A, B, C and the carrier moves them in succession to station D where they are adjusted in correct position by a vertically reciprocating plunger operated by a lever 36 and a cam 40 on a shaft 16.  At station H the mount enters a chamber 43 to protect the operator and at station J is the first dipping mechanism comprising a cup 52, Fig. 5, containing fluid fulminating material, a quantity of which is lifted around the lower portions of the wires 30 by a ladle 55 reciprocated by mechanism operated by a cam on the shaft 16.  Entry of fluid into the ladle is assisted by an orifice in the bottom closed by a ball 59.  In order to use all the fluid the ladle is adapted to enter a well 60 at the bottom of the cup.  The movements of the ladle keep the fluid well mixed and the operating cam may be shaped to give additional reciprocating mixing movements.  The fluid is maintained at the correct consistency by the addition of amyl acetate from a container above the cup 52 having a conduit leading to the cup.  The outlet from this container to the cup is controlled by a valve operated by a solenoid, the <PICT:0628529/III/1> <PICT:0628529/III/2> <PICT:0628529/III/3> current for which is controlled by a switch periodically closed by a cam driven by a constant speed motor.  At the next station K a stream of air from a nozzle supplied by a manifold 98 and directed between the wires 30 breaks any bridge of fluid that may have formed between the wires and promotes drying. The air may be heated.  Another coat of fluid is applied at station L and streams of air are directed against the coatings at stations M, N, O.  A final coat of heavier consistency is applied at station Q where the ladle-operating cam is so shaped as to withdraw the ladle quickly, then to re-immerse the wires and finally to withdraw the ladle quickly, in order to leave a bridge of material across the wires.  At station R a stream of air breaks the bridge and lifts the material up the wires.  This stream is controlled by a cam operated valve and a byepass with a reduction valve supplies a constant gentle stream of air to dry and set the material.  The streams of air may be saturated with amyl acetate.  The mounts pass another air nozzle at station S to unloading stations U-Y. The antenna wire 32 is then bent to its final position.  The top of the chamber 43 may have rupturable membranes to direct the force of any explosion harmlessly upwards. Electric lamps and calcium chloride may be used for humidity control. The fulminating composition may be potassium perchlorate, sodium chlorate and zirconium in a binder of nitrocellulose in amyl acetate. Specifications 252,395, [Class 39 (ii)], and 548,297, [Group XXI], are referred to.